As a core technology of a next-generation transport network, an OTN (Optical transport network, OTN) includes electrical layer and optical layer technical specifications. The OTN has rich OAM (Operation Administration and Maintenance, operation, administration and maintenance) functions, a powerful TCM (Tandem Connection Monitoring, tandem connection monitoring) capability, and an outband FEC (Forward Error Correction, forward error correction) capability, is capable of implementing flexible scheduling and management of a large-capacity service, and is becoming a main stream technology of a backbone transport network.
On an electrical processing layer, the OTN technology defines a “digital wrapper (Digital Wrapper)” structure with powerful functions to map and wrapper customer service data to facilitate transmission in the OTN and implement management and monitoring on the customer service data. The digital wrapper technology includes technical methods such as: mapping and a multiplexing structure of an optical channel transport unit (OUT, Optical Channel Transport Unit), time division multiplex of an optical channel data unit (ODU, Optical Channel Data Unit), time division multiplex of an optical channel payload unit (OPU, Optical Channel Payload Unit-k Overhead), and mapping of the customer service data.
With the rapid development of data services, more and more customer services need to be transmitted through the OTN. The present OTN mechanism cannot well satisfy and directly bear various services with different rates. In view of this problem, the ITU-T (International Telecommunication Union-Telecommunication Standardization Sector, International Telecommunication Union-Telecommunication Standardization Sector) is discussing on formulating a new optical transport network frame ODUflex frame to solve this problem. The ODUflex still keeps an original ODU structure and is capable of bearing the services and packet services with any constant bit rate (CBR). For different services, different mapping procedures are used to map service signals to the OPU.
The ODUflex cannot be directly sent onto a line and needs to be encapsulated in an HO ODU (Higher Order Optical Channel Data Unit, higher order optical channel data unit) and transmitted through an HO OTU (Higher Order Optical Channel Transport Unit, higher order optical channel transport unit).
At present, a mode of mapping the ODUflex to the HO ODU uses a GMP (Generic Mapping Procedure, generic mapping procedure). The ODUflex occupies several TSs (Time Slots, time slots) of the HO ODU. The GMP is a generic mapping procedure of the OTN and is specifically as follows: Generate a customer entity quantity value Cn and clock information of per service frame period; then, use the sigma-delta algorithm to calculate a distribution pattern of customer data in a payload area; and map Cn records of customer data to corresponding locations of the distribution pattern.
Due to an irregularly change feature of packet service traffic, the ODUflex needs to provide different bandwidths in different periods to satisfy different service traffic and adjust a bandwidth of an ODUflex channel without interrupting the packet service. The adjustment process relates to an adjustment of bandwidth that is occupied when the HO ODU bears the ODUflex, that is, an adjustment of TSs in the HO ODU. A GMP block container is a space that bears the ODUflex and is formed from multiple TSs. Therefore, to adapt to the changes of the packet service traffic, a mechanism is required to adjust a size of the GMP block container.